I had bid on a Green Contemporary 75 - I planned to do similar - change the colour to Starlight Silver and modify the Starspoke wheels to five spoke etc..
OUTBID - I didn't want to pay too much for the Model so i didn't bother driving the price up.
I almost bid on a Cast Pewter model 75 too - i'm sure the type that were given to those who worked on the 75 design - I expected the winning bid would be high - it sold for around £12 if i remember correct
Bargain
Paul.